This invention relates to a closure system for use in apparatuses for the interruption of the injection of liquids into cavities, in particular liquids under a relatively high pressure and/or at relatively high temperatures, such as plastics, which are injected into injection moulds via a liquid passage, defined by a central body or inner sleeve, said closure system being provided with a closure rod which can be retractably placed in a gating of the liquid passage, said closure rod having cross-sectional dimensions which are substantially equal to the dimensions of the gating.
The known closure systems all function with a closure rod which remains in the gating when the closure system is opened. Further it is a disadvantage of the known system, that the driving mechanism of the closure rod has to be positioned directly above the sprue nozzle with a spring system or a hydraulic/pneumatic cylinder, or via a lever system next to the sprue nozzle. It is also a disadvantage, that the position of the closure rod will change when the manifold is expanded because of differences in temperature.
As a result, known systems are complicated and expensive. Because the annular section of the liquid passage contacts the materials over a relatively long distance, large current resistances appear during the passage of the synthetic materials, caused by adhering forces.